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Catastrophic water change
- Thread starter idris
- Start date
Yes is the answer, but as with all test kits reliability and repeatability of hobby grade test kits is not good.
Just add Prime is best you can do assuming chloramine is always present.
Hi, i've just realised I made a mistake on the no effect concentration of sodium hypochlorite. It is 0.21 ppb not ppm and this makes a big difference. I'll have a look into acute toxic concs when I get chance and back to you.
Hi all,
It is just a more <"persistent form of chlorine disinfection"> using monochloramine (NH2Cl), the term used is "residual disinfection capability". Chloramine is persistent, and will slowly be hydrolyzed to NH3 (picking up an H+ from the water) and Cl2.
<"Water conditioners like Prime"> work by combining the ammonia into a non-toxic molecule, but it will still be picked up by ammonia tests.
If you have a large plant mass (ideally including floating or emergent plants) and do relatively small volume water changes (with added) conditioner it shouldn't be a problem.
If you add chlorine (Cl2) as your disinfectant it will out gas a long its concentration gradient with atmospheric levels of Cl2, which are extremely low (chlorine is highly reactive, so readily forms compounds NaCl etc). Chloramine disinfection just produces a constant trickle of Cl2. In terms of drinking water the small amount of NH3 produced is irrelevant, but not if you are a fish keeper.
It is because it is highly reactive and an oxidising agent that chlorine works as a disinfectant (in solution as hypochlorous acid (HCLO) and hypochlorite (CLO-)).
cheers Darrel
Measurement is tricky because you have a continual trickle of CL2 and NH3.
It is just a more <"persistent form of chlorine disinfection"> using monochloramine (NH2Cl), the term used is "residual disinfection capability". Chloramine is persistent, and will slowly be hydrolyzed to NH3 (picking up an H+ from the water) and Cl2.
<"Water conditioners like Prime"> work by combining the ammonia into a non-toxic molecule, but it will still be picked up by ammonia tests.
If you have a large plant mass (ideally including floating or emergent plants) and do relatively small volume water changes (with added) conditioner it shouldn't be a problem.
If you add chlorine (Cl2) as your disinfectant it will out gas a long its concentration gradient with atmospheric levels of Cl2, which are extremely low (chlorine is highly reactive, so readily forms compounds NaCl etc). Chloramine disinfection just produces a constant trickle of Cl2. In terms of drinking water the small amount of NH3 produced is irrelevant, but not if you are a fish keeper.
It is because it is highly reactive and an oxidising agent that chlorine works as a disinfectant (in solution as hypochlorous acid (HCLO) and hypochlorite (CLO-)).
cheers Darrel
Parablennius
Member
This is the issue with domestic water supply companies. They sell you drinking water, not "fishkeeping" water.
Absolutely no chloramines in my present area - nor in my roadworks tank disaster.
I often increase Prime dosing during summer months or if there's been heavy rains with flooding as Water Board will add additional chlorine, it's also good to know how close you may be to a chlorine dosing station (in my case not too far, on occasion I've turned on the tap & had to step back
... I don't water change then)In case of negative fish reaction post-water change I always begin by adding additional Prime - I use a Python & monitor fish closely during water changes, also keep filter running while refilling tank (I rarely turn filter off)
I have heard of people not turning their filter off and untreated tap water killing their filter and fish dying due to massive ammonia spike. Mind you Prime should prevent any ammonia spike.
xim
Member
- Joined
- 19 Mar 2010
- Messages
- 499
I use a chlorine test kit for swimming pools. It will turn yellow when there is chlorine and will be clear without.
I will add a little more de-chlore after it looks clear to cover some misreading.
I've recently switched from Prime to Seachem Safe. With the test kit, I've found that the recommended amount is far too little for the chlorine level where I live. So I'm not surprised anymore why there are reports of fish deaths in aquarium forums from people who use Safe for the first time.
Chlorine level is not static, it can change, especially for areas using surface water where the quality can be very different depending on the time of year which affects the amount of chlorine/chloramine needed to make the water safe.
I also have a NH3/NH4 test kit and used it occasionally. It never gets higher than 1 PPM. So I know what is the baseline.
I don't pray and hope for the best when using a de-chlore product.
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Right, apologies for the confusion earlier. I've now found a reliable reference.
The no effect concentration for sodium hypochlorite is reported as 0.06 ppb TRC (total residual chlorine). Assuming TRC refers to the amount of chlorine in sodium hypochlorite then the actual no effect concentration for sodium hypochlorite will be 0.13 ppb.
There is not much data reporting acute toxicity but a lethal concentration is reported as 33 - 60 ppb TRC which would = 70 - 125 ppb sodium hypochlorite - as you can see this is pretty nasty stuff.
So under these assumptions how likely is it that hypochlorite was the problem? If we use 70 ppb as the lethal concentration then you need to have at least 15.4 mg of sodium hypochlorite in your 220 L tank.
Miltons website states that the sodium hypochlorite concentration in their product is 2%.
Therefore you would need 0.77 mL in 220 L for a lethal dose. It would be good if someone could check these calculations.
This is not much liquid at all. Are there any gaps at the top of your tank where Milton could have seeped in to? If these calculations are correct then my feeling is that it could be possible that the hypochlorite caused the sudden fish death. There are other factors to consider such as the chemical stability of hypochlorite (it's very reactive) which may mean that it can be ruled out as a cause.
It's about a month since I cleaned (and then rinsed) the tank. Would any Cl not have gassed off in that time?
I wouldn't say it's just hoping for the best. I've not had anythihng like this in 15yrs of keeping fish.
zozo
Member
Even that is not the case in some countries, i've been to places where no drinking water came from the tap.. This you had to buy bottled in the store. What came from the tap tasted like pure saltwater..
Chlorine would form in the presence of strong acid so it probably would not have gassed off. The solid form is very unstable but residual amounts may have stayed in solution if there was anywhere for it to seep. I'm not sure how long the solid form would persist (e.g if the milton evaporated and left a solid residue).
You can get white crystals forming round the top of a bottle of Milton. I'm not sure what they are, so I guess this is possible, but as the only nooks and crannies that any of the solution could get to are still about 3" above the water, I'd be surprised if this is the cause.
Very very very very very careful. Pool kits shows free chlorine (ie gas) and will not indicate chloramine.
Be super super super careful, most dechlorinators will influence test kits, especially nitrate & ammonia kits will under read as they bleach the indicator dye. Chlorine test kits will give a false positive due to chloride being produced as by product of dechlorination.
Also, to the other replies, any residual sodium hypochlorite will very, almost instantly disappear once it gets in the tank as it will react with any organic compounds (ie bleaching them). Thus I would say it will be almost impossible to get any significant level of hypochlorite in you tank, which is probably why bleach is the recommended method of cleaning tanks etc. People have returned their bleach regenerated Purigen bags to their tanks, forgetting to rinse and dechlorinate the bleach first, and suffered no fish/plant/tank issues.
Please don't take my posts as judgemental in any way and I'm certainly not suggessting people don't use bleach to sanitise their equipment. I always think it's a good idea to consider all possible root causes when something tragic like this happens. Given what idris has said I think it is highly unlikely that hypochlorite is the cause but it opinion it was not inconceivable. Milton will be stable in the absence of organic matter and it could have pooled somewhere. Also the white crystals that are observed on the top of the bottle are mainly sodium chloride. If solid forms from evaporation the hypochlorite will co-crystallise with NaCl and this may confer some stability to the solid.
If hypochlorite is suddenly added to an aquaium I agree that it would react rapidly but, dependent on concentration, it would almost certainly effect the aquatic livestock as well.
Anyway, whatever the cause let's hope it doesn't happen to you again idris and once again good luck setting your aquarium up again.
xim
Member
- Joined
- 19 Mar 2010
- Messages
- 499
Very very very very very careful. Pool kits shows free chlorine (ie gas) and will not indicate chloramine.
I use the OTO type, it measures total chlorine, which includes chloramine.
iunknown
Seedling
What happened to me recently was that one of my two filters failed. Basically when both filters are running the tank is saturated with oxygen. When one fails, there is not as much oxygen available in the tank and the other filter's bacteria sucks the remaining oxygen to toxic levels, killing all the fish.
dan4x4
Member
- Joined
- 11 Nov 2013
- Messages
- 433
Its unlikely for a hydrant repair however dependant on the main that the hydrant is on, the water may of been rezoned from another area its possible that the water is fluorodated in the other area. Also when work carried out the parts etc will be sprayed with chlorine, so if you where unfortunate enough, maybe you have drawn the water in with strong chlorine. Although this is unlikely as you will of most likely noticed a strong chlorine smell.
Furthermore if you have iron mains, then rust builds up on the bottom of the pipe work, when the water supply is interrupted it can cause the sediment to be kicked up into the supply. So basically water then has a high iron content, you may not actually notice discolouration unless you have a large volume of water in a white container for e.g. a white bath. However if filling a 10 litre bucket you may not notice the sediment especially if the bucket it coloured.
Sorry to hear that your fish are gone. It may of been something else that we don't know that killed them. Its probably highly unlikely to happen again, but you can add a filter to catch the mains sediment onto your main pipework. However if you do this, its important to make sure that the filter is serviced at the correct intervals.
Furthermore if you have iron mains, then rust builds up on the bottom of the pipe work, when the water supply is interrupted it can cause the sediment to be kicked up into the supply. So basically water then has a high iron content, you may not actually notice discolouration unless you have a large volume of water in a white container for e.g. a white bath. However if filling a 10 litre bucket you may not notice the sediment especially if the bucket it coloured.
Sorry to hear that your fish are gone. It may of been something else that we don't know that killed them. Its probably highly unlikely to happen again, but you can add a filter to catch the mains sediment onto your main pipework. However if you do this, its important to make sure that the filter is serviced at the correct intervals.
